Originally hired for just a handful of Python skits, Carol Cleveland soon became the troupe's only significant female performer and a major celebrity crush for countless comedy-loving teenage boys. Now 72, the London-born, California-raised, Rada-trained glamourpuss is about to rejoin "the boys" for the reunion.

Tell us about your autobiography, PomPoms Up!Well, it's my showbiz story and I wrote it in three months. Actually, three months and one week because I went over my deadline. My dear friend Lynda La Plante gave me lots of advice. We go way back, we went to Rada together in the 60s.

La Plante wasn't the only illustrious name from your year at Rada, was she?No, I was there at a particularly good time. Ian McShane was my boyfriend and first love. His best friend was John Hurt. Tony Hopkins was there too. He sounded very much like Richard Burton at the time and we all knew he was going to make it.

Did you fall into comedy by accident?I started off doing stage work and all those cult shows – The Avengers, The Persuaders, Randall & Hopkirk (Deceased). Five years later, the BBC offered me my first comedy role in The Roy Hudd Show and it took off from there. Word got around there was this glamorous lady who could also be funny. Suddenly I was working with The Two Ronnies and Spike Milligan. A funny dolly bird, they called me. I coined the term "glamour stooge" because I was mainly the straight feed for the comedian, which was fun but not particularly rewarding. So I asked my agent to find me a juicy dramatic role. While he was looking, I got a call from John Howard Davies, who was directing the first five episodes of this BBC series called Monty Python's Flying Circus, and he cast me in four of them.

What was your first day like?I was in awe to begin with. I hadn't met them before but I knew their work from other shows and they were all frightfully witty, well-educated chaps. Then I got the scripts and they were very odd. There was none of Terry Gilliam's animation there, obviously. Sketches had very odd beginnings and often no end. I couldn't see how they were funny. The boys were falling around laughing and I came home, phoned my mother and said, "Mummy, I don't think this is going to last more than a few episodes." How wrong was I? But I soon got into it and they were wonderfully welcoming. It was like being the girl in a schoolboys' gang.

How did you become an integral part of the team?During filming, they discovered I wasn't just a pretty face. I would be as silly and outrageous as them. Michael Palin came up to me during rehearsals and said, "Carol, I'm sorry we don't have more for you to do, but we're just not very good at writing parts for women." Which they weren't. Not young women, anyway. They wrote all the time for old women, the pepperpots, but would play those beautifully themselves. But two weeks later, Michael came over again and said, "Darling, we've got a great part for you in episode nine, we've written it with you in mind." I said, "But I'm only here for the first four episodes." Eric Idle and John Cleese came over and they all said, "Carol, we want you, we don't want anyone else." So they put their big Python foot down, that big cartoon foot.

Which Python were you closest to?In the early days, John. But then he went through a funny phase when he was getting divorced from Connie [Booth]. He didn't really want to do another series but got coerced into it, so he was a bit grumpy for a while and I got to know the others better, particularly Michael. He's the one that's never changed. It's no wonder he's everybody's favourite Python because he's such a poppet.

Has Monty Python helped or hindered you?I loved every minute of Python and owe so much to them. Yet in some respects, it has been a ball and chain. I wasn't taken as seriously as sometimes I would've liked. But in the last few years, I've started being offered character roles. Then just as I think I've shaken off the old ball and chain, Python came knocking again.

How did you find out about the reunion?Out of the blue, I got a call from Eric Idle and he said we're all getting together. I immediately assumed it must be a film but Eric said, "No, we're doing the stage show". And I went, "Like we did 30 years ago at the Hollywood Bowl? With everybody? John too?" Because John hadn't joined us for our last performance, at the Royal Albert Hall in 2002 for the George Harrison memorial concert – although we had a not-too-shabby replacement in Tom Hanks. But Eric said, "Yes, John too". I hesitantly asked, "And Neil [Innes]?" but I wasn't surprised when Eric said no, because they've had a bit of a falling-out. My jaw dropped when I found out it was the O2 because it's huge.

Have you started rehearsing?Yes, this week. We don't have a great deal of time so it's a bit frantic. It's a much bigger show than before, with an ensemble of 20 singer-dancers and Arlene Phillips doing the choreography. There's all the old favourites that everyone will want to see.

Which sketch are you most looking forward to?The sketch that we've never done on stage before: The Spanish Inquisition. But because we don't have Graham [Chapman, who died in 1989], we've rejigged the parts and I'm playing the old lady who gets tortured by cushions. I'm also playing Graham's part in the Spam sketch, so I'm looking forward to that one too.

Will these 10 shows be the last ever Python gigs?Yes, they've announced that it'll be the last time they all perform on stage together. We're all in our 70s now and even doing 10 shows, with lots of costume changes, is going to be exhausting. And the guys have far more to do than me, obviously. But I have a feeling it might not be the last Python project ever. I wouldn't be surprised if they did another film.

You're often called the seventh Python but so is Neil Innes. Who deserves this accolade?We fought it out on the radio 20 years ago. A listener came on and said: "Now which one of you is the seventh Python?" And I said, "Yes, Neil, which one of us is? I think it's me." And he did concede all claims to the title!